Boom goes my fresh water tank....

CJW8 wrote:
Well my vent line is a 3/8" hose. My fill hose was 5/8" water hose with good pressure. I got distracted while filling and when I caught it, water was spraying out the vent line about 30 feet and also leaking a lot around the fill point. I had two tanks. Top was an 80 gallon tank in the pass through storage area. It was translucent plastic rectangular shaped and it looked like a basketball. I didn't look at the belly tank but it was significantly bowed out on the bottom to bend 2ea. 1 1/2" angle iron pieces.

So if the vent and the small area around the fill hose are not keeping up with the water going in, the tanks will pressure up very quickly.

A typical 40 gallon RV FW tank is 42" 26.75" 9.5" . That is 1123.5 square inches of surface area on the top and the same on the bottom of the tank. If the pressure inside the tank was only up to 0.5 PSI (pounds per square inch) then that is a force of 561.75 pounds on the top of the tank. It is also 561.75 plus the static head of 9.5 inches of water column (height of tank) = .34 PSI for a total of .84 PSI on the bottom, so it is also 943.74 pounds of force on the bottom of the tank, 127.0625 pounds of force on both ends of the tank and 199.5 pounds of force on both sides of the tank.

So yes, it is designed to carry it's rated capacity 332 pounds of total weight but it is not designed for the kinds of forces above. The forces above cause tanks to bend/break supports, burst etc.